<!DOCTYPE html>
<html>
<head>
	<title>一元运算符</title>
</head>
<body>
<script type="text/javascript">
	
	let a = 1;
	let b;
	b = ++a + ++a;		// 2-2 + 3-3
	console.log(b)

	a = 1;
	b = ++a + a++;		// 2-2 + 2-3
	console.log(b)

	a = 1;
	b = a++ + a++;		// 1-2 + 2-3
	console.log(b)

	a = 1;
	b = a++ + ++a;		// 1-2 + 3-3
	console.log(b)

</script>
</body>
</html>